31 July, 2010

Equalis - another Science 2.0 tool

A few days ago I got a message from Carmine Napolitano, who is a co-founder of recently launched Equalis project. It's a kind of new "Science 2.0" social network for sharing ideas, blogging, connecting people and tackling math-related problems together. I didn't get deeply into it, but it's worth checking out.

30 July, 2010

A story from academia

Getting a permanent job in science is extremely tough. Even if you're superbrilliant and get a tenure-track professorship, it's still very likely that you don't get through. In this case your chances for a permanent job at one of the good universities are scarce, but on the other hand you are probably too old and not competitive enough to get a good job in industry.

Recently we heard a story about Amy Bishop who killed a few people after being denied a tenure at the University of Alabama. Yesterday I was told about a chemistry Professor at MIT, who didn't get tenured after 5 years of tenure-track (acceptance rate is about 50% there). After that he gone completely crazy and joined the US army. He is in Iraq right now.

Take care,


29 July, 2010

Here is what experimentalists do for fun

Some friendly PR for a friend of mine Stasia Gonchar. She is an experimentalist and gets bored waiting for long data scans to end. As an entertainment she makes nice little sculptures like that:


(follow the link and check her other animals out)

Her deviantart page is here, some of you may like her paintings and photos as well.

Take care,


24 July, 2010

The Science article that made me speechless

In his blog post Igor Ivanov dragged attention to the following paper, that recently appeared in Science magazine:

Sinha et al. "Ruling Out Multi-Order Interference in Quantum Mechanics"

In the abstract the authors refer to unification of quantum mechanics with gravitation and such kinds of things, that somehow don't seem to be very relevant. Here is what they do.

In an optical double slit experiment two different light paths interfere with each other. That means that the resulting intensity is not given by the sum of intensities from two "one-slit" experiments, but by the square of added electromagnetic amplitudes:

I = (A1 + A2)2 = A12 + A22 + 2A1A2 = I1 + I2 + I12

In this way, in addition to one-slit amplitudes, I1 and I2, we have the interference term I12 here.

If we have three slits, all three paths will interfere with each other, and the resulting intensity will be also given by the square of the resulting amplitude:

I = (A1 + A2 + A3)2 = A12 + A22 + A32 + 2A1A2 + 2A1A3 + 2A2A3 = I1 + I2 + I3 + I12 + I13 + I23

What the authors do is they measure diffraction of light in the three-slit experiment and prove that the equation above is correct, and there is no "three-slit term" there, such as A1A2A3.

Then they explicitly state that the absence of the three-slit term means that light paths interfere with each other only in pairs, and there is no interference of three paths.

This is not correct, all three paths interfere with each other: we still sum up three amplitudes and then square them. The absence of the A1A2A3 term means that intensity is calculated as square of the amplitudes, but not cube or any higher power. However, if the intensity wasn't given by a square of the amplitude, that would be already revealed in other (even more precise) experiments with light, electrons, and atoms.

This article was highlighted in Science perspectives and Nature News, but I'm still puzzled how it passed through into the Science magazine.

20 July, 2010

Physics is useful. Even in engineering.

I'm at the Gordon conference on Atomic and Molecular interactions right now, having lots of fun. For instance, here in Colby-Sawyer College they've got "hands free towel machines" in bathrooms:

(sorry for blurry picture)

In the bottom of this thing there is an infrared trigger that rolls out the towel if you put your hand close to it.

The problem is that water absorbs infrared, and this machine works well only if your hands are already dry.


15 July, 2010

Naming kids is hard

Last year chemistry Nobel laureate Dudley Herschbach was giving a plenary talk at the Faraday Discussions conference. After the talk he got a question somehow related to angular momentum algebra and started his answer with

"You know, I love angular momentum. I even blame my parents for not naming me 'Angular momentum'!"

What puzzles me a bit is the whole 'naming kids' business. I can understand that guys far from math don't name children using indeces or primes, although 'Anna-double-prime' or 'John-three' looks and sounds great. But if people stick with the name of the mother/father while naming their dauther/son they should use something of that sort. Vladimir-prime Vladimirovich Putin, for instance.

14 July, 2010

Math is like love

There is a famous quote by R. Drabek:

"Math is like love - a simple idea but it can get complicated."

Does anyone know who this guy Drabek was (or is)? It looks like wiki has no idea about him, I cannot figure out even his first name.

Thanks for collaborating :-)


12 July, 2010

von Neumann's words come true

Everyone heard a famous quote of John von Neumann: "with four parameters I can fit an elephant, and with five I can make him wiggle his trunk".

A friend of mine Valera Yundin sent me a link to an awesome article:

Jürgen Mayer, Khaled Khairy, Jonathon Howard, "Drawing an elephant with four complex parameters", Am. J. Phys. 78, 648 (2010)

And it works!

That is definitely something to highlight in the Max Planck Research magazine :-)

Take care,